Manual paper feeding device for image forming apparatus

ABSTRACT

A manual paper feeding device for use with an image forming apparatus, which includes first and second paper trays for storing paper, the first and second paper trays being formed in parallel to each other up and down with a predetermined space therebetween in a body frame of the image forming apparatus; a pickup roller for picking up the paper stacked in the first and second paper trays, the pickup roller being set up to be rotatable in the body frame; a friction pad for separating the paper sheet by sheet, the friction pad being set up in the lower part of the pickup roller; and a paper feeding guide for guiding the feeding of the paper, the paper feeding guide being positioned between the back of paper and the friction pad, when the paper is fed to the image forming apparatus.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 2004-107819 filed Dec. 17, 2004 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Aspects of the present invention relate to an image forming apparatus such as a laser beam printer and an all-in-one printer/facsimile/copier; and, more particularly, to a manual paper feeding device for an image forming apparatus that can feed a special paper, such as a thick paper, an envelope, a postal card and the like sheet by sheet.

2. Description of the Related Art

As is well known, image forming apparatuses, such as printers and all-in-ones, include an automatic paper feeding device for feeding a general type of print paper automatically and consecutively and a manual paper feeding device for providing a special paper, such as thick paper, an envelope, a postal card and the like, sheet by sheet.

Referring to FIG. 1, a manual paper feeding device for an image forming apparatus has a first paper tray 20 and a second paper tray 30 which are formed up and down in parallel to each other in the body frame 10 of the image forming apparatus. The first and second paper trays 20 and 30 contain paper to be fed to a printing engine (not shown) in the inside of the body frame 10. Typically, general print paper is stacked in the first paper tray 20 and special paper is stacked in the second paper tray 30. If the second paper tray 30 is not provided, the special paper is loaded in the first paper feeding 20. In any case, the special paper is supposed to be loaded in a paper tray sheet by sheet.

A pickup roller 40 for picking up paper stacked in the paper tray 20 or 30 is set up to be rotatable by a shaft 11 of the body frame 10, and a friction pad 50 is set up in the lower part of the pickup roller 40 to separate a stack of paper sheet by sheet.

The manual paper feeding device for the general image forming apparatus can feed the general print paper sheet by sheet or consecutively by using the first paper tray 20 and the special paper sheet by sheet or consecutively by using the second paper tray 30.

When a sheet of paper on top of a stack of the general print paper in the first paper tray 20 is picked up by the pickup roller 40, the paper under the top sheet of paper is not fed due to a frictional force of the friction pad 50 and only the top sheet of the general print paper is fed. That is, the sheets of the general print paper can be separated, because the frictional force of the friction pad 50 is set to be higher than that between the general print paper sheets.

However, the conventional manual paper feeding device has a problem that, when special paper such as thick paper, an envelope, or a postal card is loaded sheet by sheet and fed in the first or second paper tray 20 or 30, a slipping effect occurs due to the frictional force of the friction pad 50, which leads to erroneous feeding of paper and jams.

Moreover, depending on the type of the special paper, paper feeding may not occur at all. For example, paper XEROX 3R3028, an Over Head Projector (OHP) film bonded with general print paper on one side, has a small frictional coefficient on the side of the OHP film while having a relatively large frictional coefficient on the other side. Therefore, feeding may not occur.

SUMMARY OF THE INVENTION

An aspect of the present invention provides a manual paper feeding device for an image forming apparatus that can feed paper successfully when special paper is to be fed.

An aspect of the present invention provides a manual paper feeding device for an image forming apparatus that does not have a restriction in using special paper by successfully feeding special paper including an Over Head Projector (OHP) film with general print paper bonded on one side.

In accordance with an aspect of the present invention, there is provided a paper feeding device for an image forming apparatus, which includes: first and second paper trays to store paper, the first and second paper trays being formed in parallel to each other up and down with a space sufficient to accommodate a stack of paper therebetween in a body frame of the image forming apparatus; a pickup roller to pick up the paper stacked in the first and second paper trays, the pickup roller being set up to be rotatable in the body frame; a friction pad to separate the paper sheet by sheet, the friction pad being set up in the lower part of the pickup roller; and a paper feeding guide to guide the feeding of the paper, the paper feeding guide being positioned between the back of paper and the friction pad, when the paper is fed to the image forming apparatus.

In accordance with an aspect of the present invention, the first paper tray is used to store general print paper and the second paper tray is used to store special paper, and a line end of the paper feeding guide can be moved between a paper using position, which is a position between the pickup roller and the friction pad, and a paper disusing position, which is a position away from the paper using position by a predetermined space.

In accordance with an aspect of the present invention, the paper feeding guide is placed on top of or on the bottom side of the second paper tray, and the width (W2) of the paper feeding guide is the same as the width (W1) of the pickup roller.

In accordance with an aspect of the present invention, the paper feeding guide has a frictional coefficient smaller than the frictional coefficient of the friction pad and, preferably, the frictional coefficient of the paper feeding guide is not more than 0.5. Specifically, the paper feeding guide is formed of molded plastic.

In accordance with an aspect of the present invention, in the manual paper feeding device for an image forming apparatus, because the paper feeding guide is positioned between the paper and the friction pad when special paper is supplied, the frictional force of the friction pad does not act on the paper. Thus, it is possible to prevent erroneous paper feeding caused by a slipping effect that occurs in a conventional paper feeding device when special paper is fed, and to feed any types of special paper smoothly.

In accordance with another aspect of the present invention, there is provided a paper feeding device for an image forming apparatus, which includes: a first paper tray to store general print paper, the first paper tray being set up in a body frame of the image forming apparatus; a second paper tray to store special paper, the second paper tray being set up over the first paper tray in parallel to the first paper tray; a pickup roller to pick up the paper stacked in the first and second paper trays, the pickup roller being set up to be rotatable in the body frame; and a friction pad to separate the paper sheet by sheet, the friction pad being set up in the lower part of the pickup roller; wherein a line end of the second paper tray is formed to be movable between a paper using position, which is a position between the pickup roller and the friction pad, and a paper disusing position, which is a position away from the paper using position by a predetermined space, and when special paper is fed, the second paper tray is moved to the paper using position and the special paper is set.

In accordance with an aspect of the present invention, the second paper tray is formed of molded plastic having a smaller frictional coefficient than the friction pad. Preferably, the frictional coefficient of the second paper tray is not more than 0.5.

In accordance with yet another aspect of the present invention, there is provided a paper feeding device for an image forming apparatus, which includes: a paper tray to store general print paper or special paper optionally, the paper tray being formed in a body frame of the image forming apparatus; a pickup roller to pick up the paper stacked in the paper tray, the pickup roller being set up to be rotatable in the body frame; a friction pad to separate the paper sheet by sheet, the friction pad being set up in the lower part of the pickup roller; and a paper feeding guide to guide the feeding of special paper, when the special paper is fed, the paper feeding guide being positioned between the back of special paper and the friction pad.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a perspective view showing a conventional manual paper feeding device for an image forming apparatus;

FIG. 2 is a perspective view describing a manual paper feeding device for an image forming apparatus in accordance with an embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating operation of the manual paper feeding device of FIG. 2;

FIG. 4 is a schematic diagram describing the structure and operation of a manual paper feeding device in accordance with another embodiment of the present invention; and

FIG. 5 is a schematic diagram illustrating the structure and operation of a manual paper feeding device in accordance with yet another embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.

As illustrated in FIGS. 2 and 3, a manual paper feeding device for an image forming apparatus, which is suggested in an embodiment of the present invention, includes a first paper tray 20 and a second paper tray 30 formed in a body frame 10 of the image forming apparatus up and down in parallel to each other with a predetermined space between them. The first and second paper trays 20 and 30 are loaded with a stack of paper to be fed into a printing engine (not shown) in the inside of the body frame 10 of the image forming apparatus. In the first paper tray 20, general print paper P1 is stacked, while special paper P2 is stacked in the second paper tray 30.

Although not shown in the drawings, if the image forming apparatus does not include the second paper tray 30, the general print paper P1 and special paper P2 are loaded in the first paper tray 20 and fed optionally. In any case, when the special paper P2 is used, it is supposed to be loaded in the tray sheet by sheet.

A pickup roller 40 is set up in the body frame 10 to be rotatable by a shaft 11 to pick up the paper loaded in the first and second paper trays 20 and 30. In the lower part of the pickup roller 40, a friction pad 50 is set up to separate multiple sheets of paper one from the others.

Also, a feeding guide 60 is provided between the back of the paper and the friction pad 50 when the special paper P2 such as thick paper, an envelope, or a postal card is supplied by using the second paper tray 30 to thereby prevent the frictional force of the friction pad 50 from affecting the special paper. Therefore, it is possible to prevent slipping or mispicking due to the frictional force of the friction pad 50 when special paper is fed into the image forming apparatus.

The feeding guide 60 is disposed on top of the second paper tray 30 to be movable in an arrowed direction shown in FIG. 2. The paper feeding guide 60 is set up in such a manner that a line end of the paper feeding guide 60 can be moved between a paper using position, which is a position between the pickup roller 40 and the friction pad 50, and a paper disusing position, which is a position away from the paper using position by a predetermined space. The paper feeding guide 60 can be moved manually or automatically by sensing the type of paper loaded in the tray according to embodiments.

The width (W2) of the paper feeding guide 60 is the same as the width (W1) of the pickup roller 40. The paper feeding guide 60 is formed to have the same length as the second paper tray 30. However, the present invention is not limited to the disclosed lengths and widths.

To perform required functions, the feeding guide 60 has a smaller frictional coefficient than the friction pad 50. In an aspect of the present invention, the frictional coefficient of the feeding guide 60 is equal to or smaller than 0.5. Herein, it is advantageous to form the paper feeding guide 60 of molded plastic in the respect of the frictional coefficient and of manufacturing and molding.

The manual paper feeding device for an image forming apparatus which is suggested in the present invention can feed the general print paper P1 sheet by sheet, or consecutively, by using the first paper tray 20 and the special paper P2 sheet by sheet, or consecutively, by using the second paper tray 30, as with conventional paper feeding devices.

When the general print paper P1 is supplied by using the first paper tray 20 and a single sheet of the general print paper P1 on top of a stack of the general print paper in the first paper tray 20 is picked up by the pickup roller 40, only the top sheet is fed and the other sheets of the general print paper P1 are kept from being fed owing to the frictional force of the friction pad 50.

Meanwhile, when the special paper P2 is supplied, the paper feeding guide 60 is moved into the paper using position in the second paper tray 30 to be positioned between the pickup roller 40 and the friction pad 50, which is marked with a dotted line in FIG. 3 and the special paper P2 is set in the second paper tray 30. Then, when the special paper P2 is picked up by the rotation of the pickup roller 40, the special paper P2 can be smoothly picked up and transferred because the special paper P2 is put on the paper feeding guide 60 which has a frictional coefficient far smaller than that of the friction pad 50 and thus the frictional force of the friction pad 50 does not affect the special paper. When general print paper P1 is to be fed by using the second paper tray 30, the paper feeding guide 60 is moved into the paper disusing position and the general print paper P1 is placed in the second paper tray 30.

Aspects of the present invention can feed not only special paper P2 such as thick paper, an envelope, or a postal card without an error, but also an Over Head Projector (OHP) film bonded with general print paper on the back, which cannot be fed in the conventional paper feeding devices such as shown in FIG. 1. The special paper P2 including OHP film bonded paper can be fed smoothly without an error with the paper feeding guide 60. The paper feeding guide can widen a selection range for types of paper that can be used with image forming apparatuses.

FIG. 4 is a schematic diagram describing a manual paper feeding device for an image forming apparatus in accordance with another embodiment of the present invention. As illustrated, the basic structure is similar to that of the manual paper feeding device in the above-described embodiment of the present invention. The paper feeding guide 60′ shown in FIG. 4 is disposed on the bottom side of the second paper tray 30, rather than on top of the second paper tray 30 as illustrated in FIG. 3.

Since the activities of the paper feeding guide 60′ and effects thereof are the same as that of the previous embodiment illustrated in FIG. 3, further description will not be provided herein.

FIG. 5 is a schematic diagram illustrating a manual paper feeding device in accordance with yet another embodiment of the present invention. Referring to FIG. 5, the manual paper feeding device for an image forming apparatus suggested in the present embodiment does not include any paper feeding guide which is used in the previously described two embodiments illustrated in FIGS. 3 and 4 and the function of the paper feeding guide is performed with a second paper tray 300, which is formed to be movable, just as the paper feeding guides 60 and 60′ of the previous embodiments.

In other words, a line end of the second paper tray 300 is formed to be movable between a special paper feeding position, which is a position between the pickup roller 40 and the friction pad 50, and a general print paper feeding position, which is a position away from the special paper feeding position. When special paper P2 is to be fed, the second paper tray 300 is moved into a position as marked with a dotted line in the drawing and the special paper P2 is placed in the second paper tray 300. Since the special paper P2 does not contact the friction pad 50, the special paper P2 can be fed into the image forming apparatus smoothly. When general print paper P1 is to be fed, the second paper tray 300 resumes the position marked with solid lines in the drawing and the general print paper P1 can be fed sheet by sheet or consecutively. According to aspects of the present invention, the second paper tray 300 is formed of molded plastic having a frictional coefficient not more than 0.5 approximately.

Meanwhile, although not illustrated in the drawings, even when a manual paper feeding device has only one paper tray, the manual paper feeding device can be formed to achieve the same aspects and effects by setting up the paper tray to be movable according to the above described embodiments.

As described above, when special paper is supplied, the paper feeding guide is positioned between the special paper and the friction pad. Thus, the frictional force of the friction pad does not affect the paper and the manual paper feeding device can feed any kind of special paper smoothly without a feeding error.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A paper feeding device for use with an image forming apparatus, comprising: first and second paper trays to stack paper, the first and second paper trays being disposed in parallel to each other with a space therebetween sufficient to accommodate an amount of the paper in a body frame of the image forming apparatus; a pickup roller to pick up the stacked paper in the first and second paper trays, the pickup roller disposed to be rotatable in the body frame; a friction pad to separate the stacked paper sheet by sheet, the friction pad disposed in the lower part of the body frame below the pickup roller; and a paper feeding guide to guide the feeding of the paper, the paper feeding guide being selectively positioned between a back of one sheet of the stacked paper and the friction pad, when the one sheet of the stacked paper is fed to the image forming apparatus.
 2. The paper feeding device as recited in claim 1, wherein the first paper tray is used to store general print paper and the second paper tray is used to store special paper, and a line end of the paper feeding guide is movable between a paper using position, which is a position between the pickup roller and the friction pad, and a paper disusing position, which is a position away from the paper using position by a predetermined space.
 3. The paper feeding device as recited in claim 2, wherein the paper feeding guide is placed on the bottom side of the second paper tray.
 4. The paper feeding device as recited in claim 2, wherein the paper feeding guide is placed on top of the second paper tray.
 5. The paper feeding device as recited in claim 4, wherein the width (W2) of the paper feeding guide is the same as a width (W1) of the pickup roller.
 6. The paper feeding device as recited in claim 4, wherein the paper feeding guide has a frictional coefficient smaller than a frictional coefficient of the friction pad.
 7. The paper feeding device as recited in claim 6, wherein the frictional coefficient of the paper feeding guide is not more than 0.5.
 8. The paper feeding device as recited in claim 7, wherein the paper feeding guide is formed of molded plastic.
 9. A paper feeding device for use with an image forming apparatus, comprising: a first paper tray to store general print paper, the first paper tray being set up in a body frame of the image forming apparatus; a second paper tray to store special paper, the second paper tray being set up over the first paper tray in parallel to the first paper tray; a pickup roller to pick up the general or special paper stacked in the first and second paper trays, the pickup roller being set up to be rotatable in the body frame; and a friction pad to separate the general paper sheet by sheet, the friction pad being set up in the lower part of the pickup roller; wherein a line end of the second paper tray is formed to be movable between a paper using position, which is a position between the pickup roller and the friction pad, and a paper disusing position, which is a position away from the paper using position by a predetermined space, and when the special paper is fed, the second paper tray is moved to the paper using position and the special paper is set.
 10. The paper feeding device as recited in claim 9, wherein the second paper tray has a smaller frictional coefficient than the friction pad.
 11. The paper feeding device as recited in claim 10, wherein the frictional coefficient of the second paper tray is not more than 0.5.
 12. The paper feeding device as recited in claim 11, wherein the second paper tray is formed of molded plastic.
 13. A paper feeding device for use with an image forming apparatus, comprising: a paper tray to store general print paper or special paper optionally, the paper tray being formed in a body frame of the image forming apparatus; a pickup roller to pick up the general or special paper stacked in the paper tray, the pickup roller being set up to be rotatable in the body frame; a friction pad to separate the general or special paper sheet by sheet, the friction pad being set up in the lower part of the pickup roller; and a paper feeding guide to guide the feeding of the special paper, such that when the special paper is fed, the paper feeding guide being positioned between a back of the special paper and the friction pad.
 14. The paper feeding device as recited in claim 13, wherein a line end of the paper feeding guide is formed to be movable between a paper using position, which is a position between the pickup roller and the friction pad, and a paper disusing position, which is a position away from the paper using position by a predetermined space in the paper tray.
 15. The paper feeding device as recited in claim 14, wherein the paper feeding guide is placed on a top side of the second paper tray.
 16. The paper feeding device as recited in claim 14, wherein the paper feeding guide is placed on a bottom side of the paper tray.
 17. The paper feeding device as recited in claim 15, wherein a width (W2) of the paper feeding guide is the same as a width (W1) of the pickup roller.
 18. The paper feeding device as recited in claim 15, wherein a frictional coefficient of the paper feeding guide is smaller than a frictional coefficient of the friction pad.
 19. The paper feeding device as recited in claim 18, wherein the frictional coefficient of the paper feeding guide is not more than 0.5.
 20. The paper feeding device as recited in claim 19, wherein the paper feeding guide is formed of molded plastic.
 21. A paper feeding apparatus for use with an image forming apparatus, comprising: a first paper tray to feed general print paper removably coupled with the image forming apparatus; a second paper tray to feed special paper disposed above the first paper tray, the second paper tray removably coupled with the image forming apparatus; a pickup roller disposed in the image forming apparatus to pick up the general or special paper stacked in the first and second paper trays; and a friction pad which separates the general paper one sheet at a time, the friction pad arranged below and offset with respect to the pickup roller; wherein at least a portion of the second paper tray is movable between a first position, and a second position such that when in the first position the special paper is feedable to the image forming apparatus without contacting the friction pad, and when in the second position the general paper is feedable to the image forming apparatus.
 22. The paper feeding apparatus of claim 21, wherein a frictional coefficient of the movable portion of the second paper tray is smaller than a frictional coefficient of the friction pad.
 23. The paper feeding apparatus of claim 21, wherein the frictional coefficient of the movable portion of the second paper tray is less than or equal to 0.5.
 24. The paper feeding apparatus of claim 21, wherein the movable portion of the second paper tray is formed of molded plastic.
 25. The paper feeding apparatus of claim 21, wherein the whole second paper tray is movable between the first position and the second position.
 26. The paper feeding apparatus of claim 21, wherein the movable portion of the second paper tray is a same width as the pickup roller. 